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Summary of available data from the monarch overwintering colonies in central Mexico, 1976–1991

February 1, 2021

Historical estimates of the area occupied by overwintering Danaus plexippus (monarchs) in central Mexico (between winters of 1976 and 1991) were published in García-Serrano and others (2004) and more recently in Mawdsley and others (2020). Our primary objectives were to identify the specific data that informed those estimates and, importantly, determine the degree to which the reported estimates reflect the total size of the overwintering monarch population during that period. Understanding how historical estimates of the overwintering area relate to total population size is necessary to ensure that inferences about population abundance and temporal trends are reliable, particularly as the U.S. Fish and Wildlife Service is in the process of determining if the species should be listed under the U.S. Endangered Species Act.

Citation Information

Publication Year 2021
Title Summary of available data from the monarch overwintering colonies in central Mexico, 1976–1991
DOI 10.3133/ofr20201150
Authors Erin R Zylstra, Wayne E. Thogmartin, M. Isabel Ramirez, Elise F. Zipkin
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2020-1150
Index ID ofr20201150
Record Source USGS Publications Warehouse
USGS Organization Upper Midwest Environmental Sciences Center